Electromagnetic relay with simplified structure



Oct. 11, 1966 w. D. MAYNARD ELECTROMAGNETIC RELAY WITH SIMPLIFIEDSTRUCTURE Filed Dec. 17, 1964 4 Sheets-Sheet l INVENTOR.

W. D. MAYNARD HIS ATTORNEY Oct. 11, 1966 w. D. MAYNARD 3,278,872

ELECTROMAGNETIC RELAY WITH SIMPLIFIED STRUCTURE Filed Dec. 17, 1964 4Sheets-Sheet 2 FIG. 2 8

FIG?) 4 I NVEN TOR.

W. DMAYNARD BY HIS ATTORNEY Oct. 11, 1966 w. D. MAYNARD 3, I

ELECTROMAGNETIC RELAY WITH SIMPLIFIED STRUCTURE Filed Dec. 17, 1964 4Sheets-Sheet 5 FIG. 4

INVENTOR.

BY W.D.MAYNARD HIS ATTORNEY h 1966 w. D. MAYNARD 3,278,872

ELECTROMAGNETIC RELAY WITH SIMPLIFIED STRUCTURE Filed Dec. 17, 1964FIG.9A

4 Sheets-Sheet 4 FIG. 98

FIG. IOA

FIG. IA

IIIIII'". 37

INVENTOR.

f 8% BY W.D. MAYNARD 9c HIS ATTORNEY United States Patent 3,278,872ELECTROMAGNETIC RELAY WITH SIMPLIFIED STRUCTURE Wheeler D. Maynard,Mendon, N.Y., assignor to General Signal Corporation, Rochester, N.Y., acorporation of New York Filed Dec. 17, 1964, Ser. No. 419,082 15 Claims.(Cl. 335-185) The present invention relates to relays, and morepartioularly to an electromagnetic relay having improved structural andoperating features with special emphasis on a simple, readily assembledtype of relay with a high degree of operating elficiency.

In the present invention, it is proposed to provide a relay assembly soconstructed that when the parts are placed-in their proper positions,the correct tolerances are inherently provided. These tolerances providefor efiiciency of electromagnetic operation, as well as continued longlife of operation.

It is also proposed that the number of parts he kept to a minimum, andthat the general assembling operation be a matter of merely insertingthe various parts into proper positions and then holding these partstogether by a pair of rivets.

In the assembly of most eflicient type relays, it is necessary to employhighly skilled workmen; and, it is usually necessary to have each suchrelay adjusted and tested for certain definite characteristics. However,the construction proposed by the present invention permits the use ofrelatively unskilled workmanship; and yet the parts are preciselyregistered with one another to provide a compact operating relay notrequiring further adjustment.

It is also the purpose of the vide proper alignment for the relaycontacts with appropriate contact pressures to give accuracy ofoperation. The contact pressure for each contact is provided by aclosely designed coil spring of relatively low rate inserted into therelay after the relay has been generally assembled.

Another feature of the present invention is to provide a relativelysmall number of operating contacts with each capable of carrying atleast a kilowatt of energy for controlling lamps or other heavy dutyequiment.

A further object of the invention is to provide an improvedelectromagnetic relay wherein the relative positioning of all of themovable components of the relay is precisely fixed by virtue of thefeatures inherent in the structural components of the relay.

A still further object of this invention is to provide a relay assemblywhich permits its use for various applications, and yet is made up ofcomponents that are either molded or stamped and require no machiningbut when assembled provide great accuracy in the resulting combination.

Other objects of this invention will become apparent as its descriptionis given in the specification with regard to the accompanying drawingswhich include:

FIG. 1 is an isometric view of the partially disassembled relay showinghow the core structure is attached to the rear member of the relay andhow the front member and cover are initially located by the extendingportion of the core;

FIG. 2 is a sectional top view of the relay with a portion of its coverremoved to readily illustrate the structural features of the relay whenassembled;

FIG. 3 is a side view of the relay with certain parts shown in sectionto illustrate various structures and features of the relay when it iscompletely assembled;

present invention to pro- 3,278,872 Patented Oct. 11, 1966 tribute tothe characteristics of the relay;

FIG. 6 is an isometric view of the armature hinged upon the core piece;

FIG. 7A is a sectional side view illustrated in FIG. 3, but with theposition;

FIG. 7B is a sectional side view of the armature in a pendant position;

FIG. 8 is an expanded view showing the assembling of a contact on theback member of the relay and its manner of being positioned with respectthereto as the assembling progresses;

FIG. 9A is a top view of FIG. 9B is a side view in FIG. 9A;

FIG. 9C is a sectional side view of in position;

FIG. 10A is a top view and formation procedure for a front or backcontact spring or blade;

FIGS. 10B and 10C show back and front contact points for theirrespective contact fingers;

FIG. 11A shows a movable contact finger or blade in its formedcondition;

FIG. 11B shows the contact points in position on their respectivemovable contact fingers;

FIG. 12 is a back view of the relay;

FIG. 13 is a fragmentary view to show the holding means for the relaywindow; and

FIG. 14 is a diagrammatic view to show the structure of the insertswhich hold the contact fingers or blades.

Generally speaking, and without attempting to limit the scope of thepresent invention, the relay is comprised of a back member or structureand a spool member or structure all integrally molded together in amanner that the whole back structure can be mounted on a suitablemandrel for winding the turns of insulated wire on the spool.

When the winding is completed, terminals 6 and 7 are snapped intoposition, and the ends of the windings are connected to such terminals.The pusher member PM (or card structure) is then placed in position onthe arma ture A. The armature A is then placed in a proper position withrespect to the back member and also with regard to the front of thewinding spool. The core C is then inserted into the spool and backmember through an opening in the armature to thus hold the armature inits proper position. The residual strip is inserted into position. Thecontact fingers are mounted in appropriate positions on the back memberwith suitable inserts between them to properly align them on the backmember. The front member and cover are then suitably placed intopositions appropriately receiving the core and contact fingers. Theassembly can now be riveted to hold all these members in theirappropriate positions. The coil biasing springs are placed into positionthrough the windows in the front member. The front window is thensnapped into position to complete the relay.

Referring now to FIG. 1, it will be noted that the back member BM hasthe spool member 5 molded so as to be integral therewith. There is aseparating interior space between the spool 5 and the back member BMwhich is closed at the sides as seen in FIGS. 1 and 2. This spaceprovides room for mounting the armature A and also room for aircirculation about substantially the entire surface of the spool 5 forheat radiation purposes.

of the armature hinge armature in a raised a coil terminal; of the coilterminal shown a coil terminal When the wire is wound on the spool 5,the two ends thereof can be suitably connected to their respectiveterminals 6 and 7 which the operator inserts into the back member BM.These connections from the winding on the outside of the spool to thesolder tabs on their respective terminals pass through the spaceprovided by the recess on the side of the armature A, probably best seenin FIG. 6.

A terminal 6 is shown in FIG. 9A and 9B with its retaining finger 8 inits normal biased position and the soldering tab 18 at the right end ofthe terimnal with a projection 18a. The FIG. 9C shows this terminal 6moved to the left into the opening in the back member BM until thefinger 8 snaps into position to hold the terminal within the back memberwith the projection 18a preventing the terminal 6 from further enteringthe back member BM.

Referring to FIG. 12, it will be seen that the slot for the finger 8 isbeneath the slot for the entire terminal; whereas, the slot for finger 9on terminal 7 is above the entire slot. This makes it so that the sameterminals may be used for the right and left hand sides of the relaywith their respective solder tabs extending outwardly to theirrespective sides of the relay. For example, the solder tab 18 ofterminal 6 can be seen at the left-hand side of its slot in FIG. 1.

The pusher member PM has its lower legs fitted into the slots on theforward end of the armature A as is best seen in FIG. 1. When this isdone, the rear of the armature A is fitted into the recess of the rearof the winding spool and its forward end raised so as to allow the coreC to be pushed through between armature A and pusher member PM into thehole or recess in the spool and back member.

The core C is perfectly straight and is the right size to slip throughthe center of the spool 5 and back member BM. If the core C is slippedinto position part way, then the armature A can be positioned in thespace between spool 5 and back member BM so as to have the armature slotreceive the core C which passes through it into the back member BM untilthe holes in such core C match the holes in the back member (see FIG.3). When the core is in proper position, the eyelets 10 and 11, whichare straight tubular members each with one end slightly crimped, can betemporarily pushed upwardly through the holes in the back member to holdthe core C in its position (see FIG. 3). These rivets or eyelets 10 and11 are placed in their respective holes with their crimped ends at thebottom of the back member BM so that their upwardly extending ends canreadily receive the spring contact fingers and their respectiveseparators as presently to be described. In mass production, theseeyelets are not inserted until the cover is in position.

The contact group includes six contact fingers or blades 31, 32, 33, 34,35 and 36 which are mounted in pairs between separators 41, 42 and 43.These fingers or blades can be seen in a side view shown in FIG. 3; in afront view shown in FIG. 4; and in a back view shown in FIG. 12. Two ofthese fingers are back contacts; two of these fingers are frontcontacts; and the remaining two are heel contacts movable between thefront and back points or positions. These fingers are made ofnon-oxidizing nickel silver alloy with a partial spring temper.

The finger blanks, as formed by a cutting die from fiat material, areshown in FIGS. 10A and 11A. The blanks of FIG. 10A are used for thefront and back contact fingers, while the blanks of FIG. 11A are usedfor the heel contact fingers. It is noted that at the left-hand of eachof these blanks an extending portion is die cut to have its upper andlower wings turned under to, form a connector portion. The sameformation of the connector portion of the fingers applies to both FIGS.10A and 11A. The connector portions of the finger blanks of FIG. 10A areunfolded in the upper left, but in FIG.

11A, they are folded into position. The right-hand ends of these fingersare formed with holes 19 for receiving the contact buttons or pointsthemselves. The contact finger blanks of FIG. 10A are made with two backcontacts 33 and 36 as shown in FIG. 10B, and two front contacts 31 and34 as shown in FIG. 10C. Two contact finger blanks of FIG. 11A areprovided with contacts as shown in FIG. 11B.

The contact points or buttons of FIGS. 10B, 10C and 11B are in two partshaving the base portion 37 which is of non-oxidizing nickel silver alloyType D of ASTM designation 8206-56 (annealed) as set forth in theAmerican Society for Testing and Materials, 1961, page 254. The faces 38of the points (or contacts) are preferably formed of an alloy comprisingten percent cadmium oxide and ninety percent silver. These contact facesare sweated onto their base portions. The front and back contacts ofFIGS. 10B and have their base portions inserted into the holes 19 of thecontact fingers. The portions extending through the holes are pressed,forming receiving buttons for the coil spring biasing means later to bediscussed. In FIG. llB, the two base portions of the contacts arepositioned in the hole 19 and are Welded together and to the finger by aspot welding process.

It is noted that the front and back contact fingers of FIG. 10A have theextending portions 45 adapted to rest against suitable abutments laterto be described with regard to the front member FM. The heel con-tactfingers of FIG. 11A have extending bifurcated portions 46 for coactingwith the pusher member PM later to be described.

Each of the finger blanks of FIGS. 10A and 11A are provided with a holeor slot 20 which reduces the finger cross sectional area and thusreduces the spring tension of the finger so that it is relatively weakcompared to its coil spring biasing means later to be described indetail. In addition, each finger has an opening 21 which is forreceiving a protruding portion 48 on its mounting adapted to generallyalign the finger in proper position; but the actual position of thefinger is determined by the projecting sharp prongs 39. These ovalprotruding portions 48 also give added insulation and creepage distancebetween contact fingers and the rivets 10 and 11.

To assemble the contact group, two back contact fingers 33 and 36 arefirs-t placed in position on block 40. Insert 41 is placed over the topof them and slightly pushed into position. Then two heel contact fingers32 and 35 are inserted in pusher PM and then placed in position on theinsert 41, Insert 42 is put in position and slightly pressed. The twofront contact fingers 31 and 34 are then placed in position on insert 42followed by the addition of the top insert or member 43. A presspressure can now be applied on the top member 43 so as to force all ofthe contact fingers and their inserts into a tight proper position.

Since each contact finger has the wings of its connector portion bentdownwardly and underneath, there is a slot 47 in the main block 40 forreceiving the extra thickness of such portion of contacts 33 and 36.This slot 47 can be seen in FIG. 1 and in FIG. 12 as well as in FIG. 3.Similar slots are provided on the upper and lower rear edge of each ofthe inserts 41 and 42. This structure then permits the fingers 32 and 35to be positioned as viewed in FIG. 12. Also, all inserts 41 and 42 arealike.

It will also be noted that, during this pressing process, the extensions39 on the fingers are bent upwardly as shown in FIG. 8, by the dottedlines and full lines of FIG. 8 both for positioning and lockingpurposes. It can be seen that these receiving triangular shapedindentations in the appropriate portions of member 40 and the inserts(such as insert 41 of FIG. 1) are so shaped as to have the pointreceiving portion thereof sloped as can be seen in FIG. 8. Also, theother clearances with regard to these projections 39 are in the order oftwo thousandths of an inch. Since these projections then are atsubstantially separated points on the contact finger and are accuratelypositioned, each of the contact fingers then extend appropriatelyforward of the relay. In addition, each of the inserts also has aprojection 50 (see FIG. 14) at each end for being received in analignment slot 51. These alignment slots and projections have clearancesin the order of two thousandths of an inch. Thus, the inserts properlyalign themselves.

As above explained, the pusher member PM (see FIG. 1) is attached asshown in FIG. 1 to the armature A which has receiving indentations forthe lower two projecting arms or legs of the pusher memberPM. These twoarms are spread slightly and slipped into position until they snap intothe indentations on the armature. There are two pairs of extending armson the upper portion of the pusher PM, with each pair receiving itsrespective heel contact finger. When these are snapped into position,the pusher member PM is held upright. Also, the underside of the crossmember of the pusher member PM is resting on the upper side of theextending core C in its appropriate normal position. The residual strip14 may be inserted between the lower side of core C and the spool 5before the pusher member PM is positioned. If it is not inserted then,it should be inserted before the cover is positioned.

The eyelets and 11 can now be removed, if they are in position, and thefront member FM and cover brought into position so that the core C andresidual are appropiately received by pushing the molded arms 56 and 57slightly upward. Also, the front contact fingers may need to be pushedslightly upward by passing an instrument through their respectivewindows shown in FIG. 5 so that they are above the projections 54 and55. Similarly, the back contact fingers may need to be pushed slightlybelow the projections 54 and 55. This allows the front member to takeits appropriate position with the cover being received by the backmember BM. The eyelets 10 and 11 are then inserted through the holes ofthe parts including the cover. The parts are then placed in the pressand the eyelets are caused to have their upper ends crimped to tightlyhold the relay structure together.

A coil spring 58 of suitable length and requiring compressive energy ofa given value is then passed through the window in the front member andplaced over the receiving button on the pusher member PM andsutficiently compressed that it is received by the button on the upperportion of the front member as seen in FIG. 4. In a similar way, thesomewhat shorter coil spring biasing means 60 are inserted through thewindows in the front member FM to be received by their appropriatebuttons on the frame of the front member and the buttons on theirrespective contact fingers 31, 33, 34 and 36. It is assumed thatsuitable spring compressing tools are used for this spring placingprocess.

When the above has been completed, the window W is snapped into positionbehind its four retaining nubs 61 at each of the four corners of itsreceiving recess. One of these extending nubs 61 is shown in FIG. 1 andanother in FIG. 13. These small nubs or extensions of the front memberhold the window W in place. The nub 61 in the lower left of the relayfront member FM is shown in FIG. 13. This cross sectional view showsthat the nubs 61 can be molded because of the windows in back of them asshown in FIGS. 5 and 13.

Since the assembly of the relay has been completed as above described,some of the characteristics of the relay will now be discussed.

Referring to FIGS. 1 and 3, it will be noted that the forward end of thearmature A is looped or turned counter clockwise so as to provide an end16 directly facing the spool 5 with its windings. The upper fiat surfaceof the loop is exactly in line with the lower flat surface 4 of the slotat the rear of the armature A receiving the core C. Thus, when thearmature becomes attracted, the surface 15 is flat against the residualstrip 14, and the flat surface 4 of the armature slot receiving core Ais flat against such core. Actually the armature A rocks at its hingepoint so as to have its flat portion merely assume a position restingsquarely against the flat surface of the projection 13 as shown in FIG.7A when the relay is fully energized. Looking at FIG, 7A it will benoted that there is a small space between the armature and theprojection 12 and substantially the same space is found in FIG. 3 wherethe relay is deenergized. However, should vibration or otherwise causethe armature A to move while it is in its deenergized position as shownin FIG. 3, it would merely abut against the surface of the projection12; but, does not particularly rub against the projection 12 duringregular operation.

In this connection, it will be noted that FIG. 7B is twice the size ofFIG. 7A so as to illustrate that when the armature is pendant, itassumes its lower position in accordance with the slot in the armaturerather than because of the abutments 12 and 13. In other words, thearmature is free to swing downward as limited by the slot but may abutagainst either projection 12 or project-ion 13 depending upon thecircumstances. It is noted that should the relay be vibrated so as totend to move the position of the armature while it is energized, theprojection 12 has a sufficiently broad flat surface so that the armaturein its raised position does not become attached thereto because of thefive or six degree slope of the upper surface of the slot as 'viewed inFIG. 7A. This particular construction of the armature and its hingecauses the organization to be of long life as well as to provideeffi-cient relay operation. The armature A and the core C are made ofArmco magnetic ingot iron (high purity) which is properly annealed togive it high magnetic permeability characteristics.

The plastic arms 56 and 57 are so molded integrally with the frontmember FM that they provide a continuous downward pressure on the coreC, as viewed in FIGS. 1, 4 and 5. This continual tension prevents anylooseness in the core from developing and positively positions itagainst the residual strip 14 in a permanent position.

The coil spring 58 which biases the pusher member PM and armature A to adownward position has a tension measuring approximately grams. This coilspring has linear characteristics in that substantially the samepressure is supplied to the pusher when the armature is in both itsdeenergized and energized positions. The remaining coil springs 60 forthe respective contacts are all alike and have linear characteristicssupplying approximately twenty-two grams of pressure to each of theircontacts. This is substantially greater than the contact fingerpressures which may require seven or eight grams for movement. In otherwords, any slight variation in the level or natural positioning of thecontact fingers is easily overcome by their main biasing springs. Thesebiasing springs 60 together with the weight of the armature and theother factors involved gives a net sixty to seventy grams downward pullon the armature in its released position.

The coil springs 58 and 60 are known as low rate coil springs. Inparticular, the coil springs 60 have a relatively low spring constant ofapproximately 55 grams per inch. Prior to assembly the springs areapproximately W of an inch long and, are compressed to an approximatelength of of an inch when in their assembled position within the relaystructure. This results in a spring produced contact pressure ofapproximately 22 grams. Since the armature movement is relatively smallin the order of of an inch, the contact pressure remains substantiallyconstant. In other words, the placement of the springs in theirrespective positions requires a compression which is many times greaterthan the deflection of the spring during the relay operation. For thisreason, the contact pressure remains substantially constant throughoutthe life of the relay.

From the above description with respect to the drawings, it will beunderstood that a compact relay has been disclosed which is readilyassembled and which provides simple and efficient operation. This relayhas been shown in the drawings (except FIG. 7B) at twice its plannedsize. From this it can be seen that this relay is so constructed as toprovide control for substantial surges in current and yet it isrelatively small. Once the parts have been made by casting and diecutting, they readily assemble in an accurate fashion to provide thedesired relay operation. The magnetic portion of the relay is suppliedwith an adequate cross sectional area of iron in its core and armatureas to effectively operate at an efficient point on their magnetizationcurve. The armature in surrounding the winding on the spool absorbs muchof the leakage flux and thus makes it possible for these relays to beclosely nested and yet have little or no effect on each other.

Having thus described one rather specific embodiment of the presentinvention, it is desired to be understood that this form is selected tofacilitate in the disclosure of the invention rather than to limit thenumber of forms which it may assume; and, it is to be further understoodthat various modifications, adaptations and alterations may be appliedto the specific form shown to meet the requirements of practice withoutin any manner departing from the spirit or scope of the presentinvention.

What I claim is:

1. An electromagnetic relay, comprising (a) a magnetic core;

(b) an energizing winding mounted on said core;

(c) a back insulator member mounted on the rear of said core;

(d) an armature pivotally mounted on the rear of said core and extendingaround said winding toward the front end of said core to form a workingairgap,

(e) a movable card mounted on the front end of said armature and actingto limit the opening of said working airgap by contacting the upper sideof said core;

(f) a plurality of contact blades each having one end fixed by said backinsulator member and certain of which have their extending ends carriedby said movable card to selectively engage the extending ends of thosecontact blades not carried by said movable card in accordance with theoperating position of said armature;

(g) a front insulator member having register surfaces therein forreceiving the extending end of said core and for positioning theunengaged extending ends of those contact blades not carried by saidmovable card, said insulator member having cover means integrallyconnected thereto for extending backwardly and attaching to said backinsulator member, and said front insulator member also having windowopenings therein;

(h) coil spring means operatively positioned through the window openingsin said front insulator member for biasing said card with its armaturetoward-s its released position;

(i) other coil spring means positioned through said window openings insaid front insulator member to bias the extending ends of those contactblades not carried by said movable card to their respective unengagedpositions;

(j) and a transparent window pane attachable to said front insulatormember and covering all of its window openings.

2. A relay structure according to claim 1 wherein the front insulatormember has integral spring arms adjacent the register surface forreceiving the core, which spring arms are effective to constantly. biasand hold said core against its register surfaces.

3. A relay structure according to claim 1 wherein said armature is of abroad U-shape with the forward leg of the U-shape being bent inwardly toform a working airgap.

4. A relay structure according to claim 1 wherein a strip of thinplastic sheet material is mounted on said core within said workingairgap to determine the minimum value of such airgap.

5. In an electromagnetic relay structure, a straight flat core, amoulded winding spool having a longitudinal slot for receiving saidcore, aback portion integrally moulded to said winding spool with atransverse slot crossing said longitudinal slot at right angles, anarmature having inner and outer ends, said inner end being turned andhaving an opening in the turned portion, said turned being inserted intosaid transverse slot followed by the insertion of said core into saidlongitudinal slot and through said opening in said armature, and saidarmature having a. fiat portion extending along and outside said windingspool toward said outer end, and said armature also having a reverseturn at its outer end to cause the end of said armature to face inwardlytoward said winding and thereby form a flat upper portion adjacent saidcore to provide a working airgap with said core.

6. An assembly for insulatively positioning a plurality of contact(blades of a relay or like switching device in precise alignment oneabove the other,

(a) a plurality of insulative wafers configurated to be stacked oneabove the other, each of said insulating wafers including at least onecontact slot of sufiicien-t depth and width to receive a respectivecontact blade,

(b) the side edges of said contact slot being formed with oppositelydisposed V-shaped notches having sidewalls that slope inwardly in thedirection toward the bottom surface of said contact slot,

(c) each contact blade having a width substantially the same as thewidth of its associated contact slot and being provided with V-shapedprojections at the side edges thereof adapted to mate into the V- shapednotches in the side edges of its associated contact slot when saidcontact blade is inserted into said slot, the lateral dimension betweenthe points of the V-shaped projections on a contact blade being slightlygreater than the lateral dimension between the points of the V-shapednotches when measured along the bottom surface of said contact slot;

((1) whereby said V-shaped projections on the side edges of a contactblade embedded into the sloping sidewalls of said mating V-shapednotches when the contact blade is urged against the bottom surface ofits respective contact slot when the insulating wafers are stacked oneabove the other and the resulting stack is then compressed together.

7. In an electromagnetic relay,

(a) an insulative member having a first transversely disposed openingformed therein to provide a space between first and second portions ofsaid insulative member and a second opening substantially rectangular incross-section and extending longitudinally through said first and secondportions of said insulative member, intersecting said space between saidfirst and second portions, said first portion being configurated tomount relay contact blades at a rear end of said relay and said secondportion being forward of said first portion and having a spool-likeshape,

(b) an armature adapted to be received in the transverse space :betweenthe first and second portions of said insulative member and having asubstantially rectangular aperture therein adjacent one end thereof anddisposed to be in substantial alignment with the longitudinal opening insaid insulative member when said armature is in assembled position,

(c) an elongated magnetic core substantially rectangular incross-section slidably mounted through the longitudinal opening in saidinsulative member and the rectangular aperture in said armature, saidcore being of a length such that one end thereof extends outward fromsaid insulative member forward of said second portion and, the aperturein said armature being slightly larger than the cross-section of saidcore, whereby said one end of the armature is retained within the spacein said insulative member for pivotal movement of the opposite endrelative to the forward end of said core,

(d) an energizable coil wound around the spool-like second portion ofsaid insulative member to encompass said core, and

(e) a plurality of contact blades each having one end fixedly mounted onthe first portion of said insulative member and certain of which havetheir extending ends operatively connected to said armature so as toselectively engage others of said contact blades as the armature movestoward and away from said core in accordance with the energization ofsaid coil.

8. An electnoma-gnetic relay comprising,

(a) a magnetic core,

(b) energizable winding on said core,

(c) an insulator member for fixedly mounting one end of said core, and

(d) an armature having one of its ends pivotally mounted adjacent saidone end of said core, said armature extending in the same direction asthe opposite end of said core and being curved back adjacent theopposite end of said core to have a portion thereof extending along butspaced by a working airgap from one surface of said core.

9. In an electromagnetic relay having a core structure,

(a) an armature pivotally mounted at one end with its free extending endmovable to operated and released positions relative to said core, saidarmature having a pair of oppositely disposed transverse notches at theside edges thereof adjacent its free extending end,

(b) a plurality of contact blades each having one end fixed and theother end extending substantially parallel with said armature, certainof said contact blades being movable to selectively engage those of saidcontact blades in accordance with the position of said armature, each ofsaid movable contact blades having a pair of oppositely disposedtranverse notches in the side edges thereof adjacent its extending end,and

(c) an insulative member tegrally formed, yieldable extending portionseach having a notch therein and being disposed laterally in pairs toreceive respectively said armature and said movable contact blades.

10. In a relay,

(a) a back insulator member,

(b) a magnetic core having one end aflixed to said back insulatormember,

() an energizable Winding on said core,

(d) an armature pivotally mounted adjacent said fixed end of said coreto have its free end movable towards and away from the extending end ofsaid core in accordance with the energization of said winding,

(e) a plurality of fixed and movable contact blades each having one endfixed to said back insulator member and having their free ends extendingsubstantially parallel with said core, the free ends of said movablecontact blades being operatively connected to said armature toselectively engage the fixed contact blades in accordance With movementof said armature towards and away from said core,

(f) an insulative casing open at one end and having registered surfacemeans therein at the opposite end to respectively define the position ofthe extending end of said core and the unengaged positions of saidhaving a plurality of in- 4 to mate with the ends of two said casing,and

(h) the other sidewalls of said casing being slightly longer than saiding of said casing to said back insulator member. 11. A relay asspecified in claim 10 wherein said casing includes an aperture at saidregistering end thereof adapted to receive the extending free end ofsaid core, and said casing being formed with resilient integralprojections normally extending yieldably into said aperture forresiliently retaining said core within said aperture.

12. The relay as claimed in claim 10 wherein said registering end ofsaid casing is provided with apertures to permit manipulation of theoperating elements of said relay While enclosed in said casing, andfurther including a sheet of insulating material adapted to be affixedlyattached in front of said registering end of the casing to completelyseal said registering end.

13. In a relay,

(a) a spool of insulating material having an aperture therethrough ofsubstantially rectangular cross section and a contiguous recess adjacentone thereof,

(b) a magnetic core of rectangular cross section adapted to be slidablymounted within said spool with the opposite ends extending therefrom,

(c) an energizable coil wound around said spool,

(d) an armature pivotally mounted adjacent one end of said core andextending outside said spool to the opposite end of said core but spacedtherefrom to form a working airgap,

(e) an insulated frame including a rectangular aperture adapted toreceive the forward end of said core, and

(f) a sheet of non-magnetic material configurated to i be supported atone end by the recess formed in the forward portion of said spool and atits other end within the core supporting aperture in said insulativeframe, whereby said sheet of non-magnetic material is disposed along onesurface of said core to serve as the residual airgap of said relayduring operation of said armature.

14. In a relay,

(a) a magnetizable core,

(b) an armature pivotally mounted adjacent one end of said core andextending towards but spaced by armature, (d) a frame of insulatingmaterial secured to the exend with a contact element, and

(e) spring means operatively positioned in said insulating framedirectly in alignment With the contact elements of each fixed contactblade for continually biasing each fixed contact blade towards itsunengaged position.

15. The relay specified in claim 14 wherein (a) each fixed contact bladeincludes a hole adjacent its extending end, and including firstsidewalls to overlap a portion; of said back insulator member to permitthe anchor- 1 1 l 2 (b) a button like member configurated to be receivedReferences Cited by the Examiner in said hole and being formed at onesurface to re UNITED STATES PATENTS ceive the contact element associatedwith that fixed 2,632,071 3/1953 Rlnke 200-87 contact blade and beingshaped at its opposing surface in the form of a spring seat for mountingthe 5 associated spring means utilized to bias said fixed BERNARDGILHEANY Prlmary Exammer' contact blade towards its unengaged position.J. J. BAKER, Assistant Examiner.

1. AN ELECTROMAGNETIC RELAY, COMPRISING (A) A MAGNETIC CORE; (B) ANENERGIZING WINDING MOUNTED ON SAID CORE; (C) A BACK INSULATOR MEMBERMOUNTED ON THE REAR OF SAID CORE; (D) AN ARMATURE PIVOTALLY MOUNTED ONTHE REAR OF SAID CORE AND EXTENDING AROUND SAID WINDING TOWARD THE FRONTEND OF SAID CORE TO FORM A WORKING AIRGAP, (E) A MOVABLE CARD MOUNTED ONTHE FRONT END OF SAID ARMATURE AND ACTING TO LIMIT THE OPENING OF SAIDWORKING AIRGAP BY CONTACTING THE UPPER SIDE OF SAID CORE; (F) APLURALTIY OF CONTACT BLADES EACH HAVING ONE END FIXED BY SAID BACKINSULATOR MEMBER AND CERTAIN OF WHICH HAVE THEIR EXTENDING ENDS CARRIEDBY SAID MOVABLE CARD TO SELECTIVELY ENGAGE THE EXTENDING ENDS OF THOSECONTACT BLADES NOT CARRIED BY SAID MOVABLE CARD IN ACCORDANCE WITH THEOPERATING POSITION OF SAID ARMATURE; (G) A FRONT INSULATOR MEMBER HAVINGREGISTER SURFACES THEREIN FOR RECEIVING THE EXTENDING END OF SAID COREAND FOR POSITIONING THE UNENGAGED EXTENDING ENDS OF THOSE CONTACT BLADESNOT CARRIED BY SAID MOVABLE CARD, SAID INSULATOR MEMBER HAVING COVERMEANS INTEGRALLY CONNECTED THERETO FOR EXTENDING BACKWARDLY ANDATTACHING TO SAID BACK INSULATOR MEMBER, AND SAID FRONT INSULATOR MEMBERALSO HAVING WINDOW OPENINS THEREIN, (H) COIL SPRING MEANS OPERATIVELYPOSITIONED THROUGH THE WINDOW OPENINGS IN SAID FRONT INSULATOR MEMBERFOR BIASING SAID CARD WITH ITS ARMATURE TOWARDS ITS RELEASED POSITION;(I) OTHER COIL SPRING MEANS POSITIONED THROUGH SAID WINDOW OPENINGS INSAID FRONT INSULATOR MEMBER TO BIAS THE EXTENDING ENDS OF THOSE CONTACTBLADES NOT CARRIED BY SAID MOVABLE CARD TO THEIR RESPECTIVE UNGAGEDPOSITIONS; (J) AND A TRANSPARANT WINDOW PANE ATTACHABLE TO SAID FRONTINSULATOR MEMBER AND COVERING ALL OF ITS WINDOW OPENINGS.